Techniques for highly accurately cutting objects to be processed having various laminate structures such as those in which semiconductor active layers such as GaN are grown as crystals on an Al2O3 substrate for semiconductor devices and those in which glass substrates are bonded to other glass substrates for liquid crystal display devices have recently been in demand.
For cutting the objects to be processed having these laminate structures, it has conventionally been common to use a blade dicing or diamond scribe method.
The blade dicing method is a method in which an object to be processed is cut by being shaved with a diamond blade or the like. On the other hand, the diamond scribe method is a method in which a diamond point tool forms a scribe line on the front face of an object to be processed, and a knife edge is pressed against the rear face of the object along the scribe line, so as to break and cut the object.
However, sawdust or lubricant/washing water may enter a gap formed between a glass substrate and another glass substrate in the blade dicing method when the object is one for a liquid crystal display device mentioned above, for example.
In the diamond scribe method, on the other hand, a scribe line must be formed on not only the front face but also the rear face of the object when the object includes a substrate having a high hardness such as an Al2O3 substrate or when the object is one in which glass substrates are bonded together, whereby errors in cutting may occur because of a misalignment between the respective scribe lines formed on the front and rear faces.